1. Field of the Invention
The present invention is related to booting a computer system from backup, and more particularly, to working with backed up data without restoration of the data to the data storage device of computer system. The present invention is also related to writing data to the backup, which can be stored on a hard disk drive, a CD/DVD writeable/rewritable disk, on a flash drive, or on a network data storage device; to an incremental backup, or to any type of the writable data storage device.
2. Description of the Related Art
Conventionally, a backup is a copy of data of the data storage device. A copy of the data can be used to restore the original state of the data storage device after a data loss event, such as computer system failure. In general, backups are used for two purposes: for restoring a computer system to a previous state, and for restoring selected files from backup.
After a file system failure, for example, the computer system cannot be started. In this case, it is necessary to boot up the computer from the other bootable media, such as a bootable CD/DVD, to restore the file system or install the OS and the necessary software on the computer system, or both.
In this case, the CD/DVD can contain software for installing an OS or a previously backed up state of the data storage device of the computer system. In each of these cases, it takes some time to restore operation of the computer system. In corporate networks, a typical server can have 200-500 Gigabytes (or, frequently, much more than that) of data. With a transfer rate up to 100 Megabytes per second over a network, it would take over 2,000 seconds to transfer all the data from the backup storage to the server's local storage. This assumes that the entire network bandwidth is available for this process. Frequently, this is not the case, since only a fraction of the bandwidth may actually be available at any given time for restoring the files from backup. In practice, such transfers of data from backup to the server can take many hours.
Also, even 2,000 seconds of downtime is an extremely long time, particularly for many mission-critical applications. For example, if the server in question is a web server that handles customer requests or sales, a period of 20-40 minutes of downtime can result in substantial lost sales.
But if data from the backup cannot be restored to the data storage device, or if the user wants to work with the data in the backup, but does not want to restore a computer using that data (for example, when the data storage device is corrupted and must be replaced, but another data storage device is not available now, or when the computer system has no data storage device and works via a network with a file system that is installed on the other computer system, such as server), then the storage media with the backup and the additional environment can be used, which provides the computer system working with the backup a data storage media from which it can be rebooted.
In other words, there is a need in the art to boot the computer system using the data in a previously created backup, read the data from the backup as if from the usual data storage device, write data both to the backup, if it is located on the writeable data storage device, and to the incremental backup, and to the any writeable data storage device, such as CD/DVD writeable/re-writeable disk, hard disk drives, flash drives, tapes, network data storage devices, and others.